Method of annealing or heat-treating steel or other metals



' -malized'and annealed without subjecting the surface thereof to oxidation and discolora-- Patented o'ci. 11,1927;

UNITED/STATES.

PATENT, OFFICE.

. EWALTER GUIBERT, or nnraorr, MICHIGAN.

METHOD or .ANNEALING on rmarrnna'rmo s'rnnn OR OTHER ME ALS.

My invention relates to a method of annealing or heat-treating steel or other metals.-

It has to do particularly with a novel method of annealing steelor other metalsin such amanner that the steel will be properly nortion during the-treating process, There is also a heavy oxide formed on metals, es-

pecially alloy metals when the same are heat treated by raising to high heat, then hardened .by quenching. Thenas a rule, they are drawn back, or-no-rmalized or tempered at a lower heat. This produces a still heavier oxide. It. is the object of my invention to avoid the formation of the oxide by performing these operations in a vacuum or a rarified atmosphere.

I In the past, especially 1n the art of an nealing steel and other similar metals, many difi'erent methods have beeniresorted to in an attempt to improve the physical properties at the steel and remove the strains and other objectionable characteristics which are always set up during the initial rolling or formation of the article to be annealed. Some 'of these methods have} contemplated the placing of-the-article to-be treatedin a uniform compa'rtment'containing a neutral atmosphere. Other methods'have involved the placing of the steel" or other metals in a compartment. orannealing box and surrounding the'stecl with iron filings, carbon -monoxide, or other non-oxidizing gase.

Many other methods have been utilized in the heat-treating of steel and some of these methods have been commercially successful in the proper treating of the core of the article.

have invariably failed to prevent the formation of scale and discolorationof the surmay be accomplished in various ways and by. various apparatus,- all of which are well However,- none, of these methods have been completely successful in that they Application filed October-'24, 1925. Serial 'No. 64,692. Y

known in the art, anddo not require draw- 4 ings for. illustration. .--For instance, the

heating compartment may be filled with the,

metals to be heat-treated, the air exhausted by a vacuum pump, or the compartment may be filled with steam which may be con- 1 densed, or drained out, or other suitable means for "securing a vacuum may be -.em'-.

ployed. The compartment is sealed, and the sealed compartmentplaced in asuitable furnace for heating the metals. The metal in the vacuum compartment may be heated conduction as directly by electric resistance.

Where it 'is desired to anneal and heat-' treat cold rolled stripor sheet steel or cope per and brass by. a continuous action, the

entire reel of metal together with the receiving reel may be placed in a compartment which may be. subJected to vacuum and the reel-is subjected .toheat y conduction as by electricresistance. 'Y Many other forms of construction mayfbe utilized in practising my method..- However. the present invention is not directed to the apparatus ordetails for effecting the vacuum or for heating the steel, but broadly to the method-of subjecting the metal to be .treated' to a vacuum during thetreating process.

It vacpum in the annealing or vacuum chamber need not be fixed to effecttfthe successful.

working of my method. The oxidation and d scoloration will be preventedto a marked degree byeven a small amount-"fvacuum, but it will also'be understood-. at by pro-' creating chamber; andxby maintaining this vacuum during the heating process, and cool- 1 in-g off, that practically all tendency of the surface of the steel .or other metal to oxidize or discolor will be prevented. In other metal-in passing from me (reel to the other" 'llbe understood thatthe degree'of ducing a large degree ofva'cuum'in'the heat words, the improvement in the physical properties of the. meta-l and the neutralizae .tion of the oxidizinginfiuen ce to effect the color and texture of. its'surface will depend proportionately 'onthe degree. of vacuum obtaining in the. annealing chamber or around the metal during the annealing processor heat treatingprocess.

It will be'understood that in using the term .vacuum in theclaims I do not limit myself to a theoretically per-feet vacuum, but that such term includes any partial vacuum, less than atmospheric pressure.

What-I claimis: I Y

1. The method of heat-treating steel or other metals adapted to be'ha-r'dened by heattreating which consists in heating the metal to the proper degree and then quenching,

the metal being maintained in a vacuum dur 1 ing the .entireiproc'ess. I

2. The method of-heat-tre sting steel or signature;

other metals adapted to be hardened by heattreating, which consists in heating the metal to the proper degree and then quenching to effect the heat-treating thereof, and sur- .rounding the metal with a vacuum to pre- Vent-pxidization and discoloration of the surface during the entire heat-treating process.

In testimony. whereof I l 13V afiixed my F W 'rpR GUIBEBT. 

